Games like Subsomnia
Games like Subsomnia include Hades, UnderMine, Hades II, Cinderia, and The Binding of Isaac. We matched them by the tags players give Subsomnia on Steam (Roguelite, Action Roguelike, Procedural Generation, 2.5D, and Atmospheric): closest matches first, and among equally close ones the better-known games.

Hades
Shared: Roguelite · Action Roguelike · Action

UnderMine
Shared: Roguelite · Action Roguelike · Dungeon Crawler

Hades II
Shared: Roguelite · Action · Action Roguelike

Cinderia
Shared: Action Roguelike · Roguelite · Action

The Binding of Isaac
Shared: Action Roguelike · Procedural Generation · Action

Dead Cells
Shared: Action Roguelike · Roguelite · Adventure

Skul: The Hero Slayer
Shared: Action Roguelike · Action · Roguelite

PEAK
Shared: Procedural Generation · Adventure · Action Roguelike

Heroes of Hammerwatch II
Shared: Action Roguelike · Roguelite · Action

Lost Castle
Shared: Action Roguelike · Roguelite · Dungeon Crawler

Heroes of Hammerwatch
Shared: Roguelite · Action Roguelike · Dungeon Crawler

The Binding of Isaac: Rebirth
Shared: Action Roguelike · Dungeon Crawler · Indie

Shape of Dreams
Shared: Action Roguelike · Roguelite · Action

Moonlighter
Shared: Roguelite · Action Roguelike · Dungeon Crawler

INSIDE
Shared: 2.5D · Atmospheric · Puzzle

Dungreed
Shared: Action Roguelike · Roguelite · Action

Streets of Rogue
Shared: Roguelite · Action Roguelike · Action

Noita
Shared: Dungeon Crawler · Action Roguelike · Physics

LIMBO
Shared: Puzzle · Atmospheric · Indie

Content Warning
Shared: Procedural Generation · Action Roguelike · Action

NECROPOLIS: BRUTAL EDITION
Shared: Action Roguelike · Roguelite · Action

Dreamscaper
Shared: Roguelite · Action Roguelike · Action

Vampire Survivors
Shared: Action Roguelike · Roguelite · Action

Wizard of Legend
Shared: Action Roguelike · Roguelite · Dungeon Crawler